JP7606969B2 - Power supply device, electric vehicle using the same, and power storage device - Google Patents

Description

The present invention relates to a power supply device and an electric vehicle and a power storage device using the same.

Power supplies are used as power supplies for driving electric vehicles and power supplies for storing electricity. Such power supplies are made by stacking a plurality of battery cells that can be charged and discharged. It is also known that the exterior can of the battery cells expands when the cells are charged and discharged. In general, as shown in the perspective view of FIG. 12, a power supply unit 900 has end plates 903 arranged on both end faces of a battery stack in which battery cells 901 in rectangular exterior cans are alternately stacked with insulating spacers 902, and the end plates 903 are fastened together with a metal bind bar 904. In addition, such a power supply unit 900 is fixed to an electric vehicle or the like by fastening the end plates and bind bars with bolts via brackets 960 as shown in FIG. 13.

On the other hand, in response to the demand for higher capacity in recent years, the number of stacked battery cells that make up the battery stack tends to increase. In such a configuration, the amount of expansion of each battery cell accumulates, and the amount of elongation of the entire battery stack increases. As a result, there is a problem that a large load is applied to the fixing point of the bracket that fixes the power supply device to an electric vehicle, etc. For example, for a power supply device 900 having a length as shown in the side view of FIG. 13, if the number of stacked battery cells is increased as in the power supply device 700 shown in the side view of FIG. 14, the amount of elongation accumulates and increases according to the number of stacked battery cells, and as a result, the stress load applied to the fixing point of the bracket 760 that fixes the power supply device 700 also becomes excessive, raising concerns about fatigue and deterioration.

In addition, in the configurations of Figures 13 and 14, brackets 960, 760 are fixed to the bind bars 904, 704 that fasten the battery cells. As the length of the battery stack increases, the bind bars that are subjected to the expansion force also become longer, increasing the amount of elongation, which further increases the stress on the brackets.

If we tried to prepare brackets and bolts that could accommodate this amount of elongation, we would have to change the bracket material to a more expensive type, increase the plate thickness, or increase the bolt diameter and number, which would result in increased costs and weight.

International Publication No. 2018/012224

One of the objects of the present invention is to provide a power supply device that prevents a large load from being placed on the fixing structure that fixes the device to an electric vehicle, etc., even when the battery stack becomes long, and an electric vehicle and a power storage device that use the same.

A power supply device according to one aspect of the present invention is a power supply device for fixing to a device to be powered, and includes a plurality of battery cells having rectangular outer cans, a pair of end plates covering both side ends of a battery stack formed by stacking the plurality of battery cells, a lower plate covering the underside of the battery stack, a plurality of fastening members that are plate-shaped extending along the stacking direction of the plurality of battery cells and are respectively arranged on opposing sides of the battery stack and fasten the end plates together with the battery stack placed on the upper surface of the lower plate, a plate fixing mechanism for fixing the lower plate to the device to be powered, and a connecting structure that connects the lower plate and the fastening members in a state that allows displacement.

With the above configuration, the lower plate, which is not affected by the expansion of the battery cells, is fixed to the device to which power is supplied by the plate fixing mechanism, rather than the end plate or fastening members, which are affected by the expansion of the battery cells. This prevents stress from concentrating on the plate fixing mechanism due to the expansion and contraction of the battery cells, and enables the power supply unit to be stably fixed to the power supply device.

1 is an exploded perspective view showing a state in which the power supply device according to the first embodiment is fixed to a power supply target device. FIG. 2 is an exploded perspective view of the power supply device of FIG. 1 as viewed obliquely from above. 3 is an exploded perspective view of the power supply device of FIG. 2 as viewed obliquely from below. FIG. 3 is a further exploded perspective view of the power supply device of FIG. 2 . 2 is a vertical cross-sectional view of the power supply device of FIG. 1 taken along line VV. FIG. 11 is an enlarged cross-sectional view showing a heat transfer sheet according to a modified example. 2 is an enlarged cross-sectional view of a main portion showing a plate fixing mechanism and a connecting structure of FIG. 1 . 2 is a schematic side view showing a state in which a battery stack in the power supply device of FIG. 1 is displaced. FIG. 1 is a block diagram showing an example of a power supply device mounted on a hybrid vehicle that runs on an engine and a motor. FIG. 1 is a block diagram showing an example in which a power supply device is mounted on an electric vehicle that runs only on a motor. FIG. 11 is a block diagram showing an example of application to a power supply device for power storage. FIG. 13 is an exploded perspective view showing a conventional power supply device. 4 is a side view showing a state in which the power supply device is fixed to an electric vehicle or the like via a bracket. FIG. 13 is a side view showing how the power supply device with the elongated battery stack is fixed to an electric vehicle or the like via a bracket. FIG.

An embodiment of the present invention may be characterized by the following configuration:

In one embodiment of the power supply device of the present invention, the plate fixing mechanism is a fixing device for fixing the lower plate to a bracket for fixing the lower plate to the equipment to be supplied with power.

A power supply device according to another embodiment of the present invention is a power supply device for fixing to a device to which power is supplied, and includes a plurality of battery cells having rectangular exterior cans, a pair of end plates covering both end faces of a battery stack in which the plurality of battery cells are stacked, a lower plate covering the lower face of the battery stack, a plurality of fastening members that are plate-shaped extending along the stacking direction of the plurality of battery cells and arranged on opposite sides of the battery stack, and fasten the end plates together in a state in which the battery stack is placed on the upper face of the lower plate, a bracket for fixing the lower plate to the device to which power is supplied, a fastener for fixing the lower plate to the bracket, and a connecting structure for connecting the lower plate to the fastening member in a state that allows displacement. With the above configuration, the lower plate, which is not affected by the expansion of the battery cells but is not affected by the expansion of the end plate or fastening member, is fixed to the bracket with a fastener, and the power supply device is fixed to the device to which power is supplied via the bracket, thereby avoiding the situation in which stress is concentrated on the bracket due to the expansion or contraction of the battery cells, and the power supply device can be stably fixed to the power supply device.

In addition, in another embodiment of the power supply device of the present invention, the bracket is fixed in a position in which it protrudes from each of the pair of end plates.

In a power supply device according to another embodiment of the present invention, the plate fixing mechanism is composed of a plate fixing screw hole formed in the lower plate, a bracket fixing hole opened in the bracket, and a plate fixing bolt inserted into the plate fixing screw hole and bracket fixing hole, and the plate fixing bolt inserted into the plate fixing screw hole and bracket fixing hole is configured so that its upper surface is lower than the main surface of the lower plate. With the above configuration, when the lower plate is fixed to the bracket by the plate fixing mechanism, the plate fixing bolt does not protrude from the plate fixing screw hole to the upper surface, thereby preventing the plate fixing bolt from hindering the displacement of the battery stack due to expansion or contraction of the battery cells on the upper surface of the lower plate.

Furthermore, in a power supply device according to another embodiment of the present invention, the connection structure includes an elongated hole formed in either the fastening member or the lower plate, extending along the stacking direction of the plurality of battery cells, a hole formed in the other of the fastening member or the lower plate at a position corresponding to the elongated hole, and an elongated screw that is inserted through the elongated hole and the hole and screwed into a state that allows relative displacement of the interface between the lower plate and the fastening member. With the above configuration, it is possible to maintain the connection between the lower plate and the fastening member while allowing displacement at the interface between the fastening member and the lower plate, which is displaced due to expansion and contraction of the battery cells.

In yet another embodiment of the power supply device of the present invention, the connection structure further comprises a round hole formed in the center of the stacking direction of the plurality of battery cells in either the fastening member or the lower plate, and a round hole screw screwed into the other of the fastening member or the lower plate at a position corresponding to the round hole, and the long hole is formed in either the fastening member or the lower plate at both ends of the stacking direction of the plurality of battery cells, and the long hole screw is screwed into the other of the fastening member or the lower plate at a position corresponding to the long hole. With the above configuration, it is possible to fix the center in the longitudinal direction, which has little displacement, by screwing in the round hole and the round hole screw, while allowing some displacement in the longitudinal direction for the ends, which have relatively large displacement, as long holes.

Furthermore, in a power supply device according to another embodiment of the present invention, the plate fixing mechanism and the connecting structure are formed coaxially, the plate fixing screw hole formed in the lower plate constituting the plate fixing mechanism is a hole portion formed in the lower plate constituting the connecting structure, and the plate fixing bolt inserted into the plate fixing screw hole and bracket fixing hole constituting the plate fixing mechanism is a long hole screw that is inserted through the hole portion constituting the connecting structure and screwed into a state that allows relative displacement of the interface between the lower plate and the fastening member.

Furthermore, the power supply device according to another embodiment of the present invention further includes a heat transfer sheet interposed between the upper surface of the lower plate and the lower surface of the battery stack, thermally coupling the lower plate and the battery stack.

Furthermore, in another embodiment of the power supply device of the present invention, the heat transfer sheet is made of an elastic insulating material.

Furthermore, in another embodiment of the power supply device of the present invention, the rectangular aspect ratio of the battery stack in a plan view is 5 or greater.

Furthermore, an electric vehicle according to another embodiment of the present invention comprises any of the power supply devices described above, a motor for driving that is supplied with power from the power supply device, a vehicle body mounting the power supply device and the motor, and wheels driven by the motor to drive the vehicle body.

Furthermore, a power storage device according to another embodiment of the present invention comprises any of the power supply devices described above and a power supply controller that controls charging and discharging to the power supply device, and the power supply controller enables charging of the battery cells using external power and controls charging of the battery cells.

The following describes an embodiment of the present invention based on the drawings. However, the following embodiment is an example for embodying the technical idea of the present invention, and the present invention is not limited to the following. In addition, this specification does not specify the members shown in the claims to the members of the embodiment. In particular, the dimensions, materials, shapes, and relative positions of the components described in the embodiment are not intended to limit the scope of the present invention, and are merely explanatory examples, unless otherwise specified. The size and positional relationship of the components shown in each drawing may be exaggerated to clarify the explanation. Furthermore, in the following explanation, the same name and symbol indicate the same or similar components, and detailed explanations will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured with the same material so that multiple elements are used by one material, or conversely, the function of one material can be shared by multiple materials. In addition, the contents described in some examples and embodiments may be applicable to other examples and embodiments.

The power supply device according to the embodiment is used for various purposes, such as a power supply mounted on an electric vehicle such as a hybrid car or an electric car to supply power to a driving motor, a power supply for storing power generated by natural energy such as solar power generation or wind power generation, or a power supply for storing late-night power, and is particularly used as a power supply suitable for large power and large current applications. In the following example, an embodiment applied to a power supply device for driving an electric vehicle will be described.
[Embodiment 1]

A power supply device 100 according to a first embodiment of the present invention is shown in Figures 1 to 8. In these figures, Figure 1 is an exploded perspective view showing how the power supply device 100 according to the first embodiment is fixed to a power supply target device PD, Figure 2 is an exploded perspective view of the power supply device 100 of Figure 1 seen obliquely from above, Figure 3 is an exploded perspective view of the power supply device 100 of Figure 2 seen obliquely from below, Figure 4 is a further exploded perspective view of the power supply device 100 of Figure 2, Figure 5 is a vertical cross-sectional view taken along line V-V of the power supply device 100 of Figure 1, Figure 6 is an enlarged cross-sectional view showing a heat transfer sheet 40 according to a modified example, Figure 7 is an enlarged cross-sectional view of a main portion showing the plate fixing mechanism and connecting structure of Figure 1, and Figure 8 is a schematic side view showing a state in which the battery stack 10 in the power supply device 100 of Figure 1 is displaced.
(Power supply target device PD)

The power supply device 100 is fixed to a power supply target device PD, such as an electric vehicle, via a bracket 60. In the example of Fig. 1, the power supply device 100 is housed in a recess DI formed in the electric vehicle, and both ends of the power supply device 100 in the longitudinal direction are fixed via the bracket 60.
(Bracket 60)

As shown in Figures 2 and 3, the bracket 60 is composed of a metal piece bent in a stepped shape, and when fixed to the power supply unit 100, it is fixed in a position where it protrudes from each of the pair of end plates 20. The shape of the bracket 60 is one example, and any shape that can be fixed to the power supply target device can be used. Also, the power supply unit may be directly fixed to the power supply target device PD without using a bracket. In the power supply unit in this specification, the bracket is optional, and the term "power supply unit" includes both a configuration including a bracket and a power supply unit without a bracket. Figures 2 and 3 show the power supply unit 100 including the bracket 60. Also, Figure 4 shows the power supply unit 100 without a bracket.

1, the power supply device 100 is provided with a plate fixing mechanism 6 on a lower plate 50 (described in detail later) for fixing the power supply device 100 to the power supply target device PD. When the power supply device 100 is fixed to the power supply target device PD using a bracket 60, the plate fixing mechanism 6 serves as a fixing tool for fixing the lower plate 50 to the bracket 60.
(Power supply device 100)

As shown in Figures 2 to 4, the power supply unit 100 comprises a battery stack 10 formed by stacking multiple battery cells 1, a pair of end plates 20 covering both side ends of the battery stack 10, a battery side plate 14 arranged on the bottom surface of the battery stack 10, multiple fastening members 15 fastening the end plates 20 together, a heat transfer sheet 40 arranged on the underside of the battery stack 10, and a lower plate 50 arranged on the underside of the heat transfer sheet 40.

The fastening members 15 are formed in a plate shape extending along the stacking direction of the multiple battery cells 1. The fastening members 15 are disposed on the opposing side surfaces of the battery stack 10, and fasten the end plates 20 together with the battery stack 10 placed on the upper surface of the lower plate 50.

The battery side plate 14 is disposed on the bottom side of the battery stack 10 and is fixed with fastening members 15. The battery side plate 14 is made of a metal plate or the like. The battery side plate 14 and the bottom surface of the battery stack 10 are insulated from each other via an insulating sheet or the like.

The lower plate 50 dissipates heat from the battery stack 10, which is placed on its upper surface via the heat transfer sheet 40. The heat transfer sheet 40 is also interposed between the upper surface of the lower plate 50 and the lower surface of the battery stack 10, stabilizing the thermal coupling state between the lower plate 50 and the battery stack 10. As a result, even if the battery stack 10 generates heat due to charging and discharging of the battery cells 1, the heat is conducted to the lower plate 50 via the heat transfer sheet 40 and dissipated.
(Battery stack 10)

As shown in FIGS. 2 to 4, the battery stack 10 includes a plurality of battery cells 1 each having positive and negative electrode terminals 2, and bus bars (not shown) that are connected to the electrode terminals 2 of the plurality of battery cells 1 and connect the plurality of battery cells 1 in parallel and in series. The plurality of battery cells 1 are connected in parallel and in series via these bus bars. The battery cells 1 are secondary batteries that can be charged and discharged. In the power supply device 100, a plurality of battery cells 1 are connected in parallel to form parallel battery groups, and a plurality of parallel battery groups are connected in series to connect many battery cells 1 in parallel and in series. The power supply device 100 shown in FIG. 4 forms the battery stack 10 by stacking a plurality of battery cells 1. A pair of end plates 20 are also arranged on both end faces of the battery stack 10. Ends of fastening members 15 are fixed to the end plates 20 to fix the stacked battery cells 1 in a pressed state.
(Battery cell 1)

Battery cell 1 is a prismatic battery with a rectangular outer shape on the main surface, which is the wide surface, and a constant cell thickness, with the thickness being thinner than the width. Furthermore, battery cell 1 is a secondary battery that can be charged and discharged, and is a lithium-ion secondary battery. However, the present invention does not specify the battery cell as a prismatic battery, nor does it specify it as a lithium-ion secondary battery. All batteries that can be recharged can be used as battery cells, such as non-aqueous electrolyte secondary batteries other than lithium-ion secondary batteries, and nickel-metal hydride battery cells.

The battery cell 1 is configured such that an electrode assembly, which is made up of stacked positive and negative electrode plates, is housed in an outer can 1a, which is then filled with an electrolyte and sealed airtight. The outer can 1a is formed into a square cylindrical shape with a closed bottom, and its upper opening is airtightly closed with a metal sealing plate 1b. The outer can 1a is manufactured by deep drawing a metal plate such as aluminum or an aluminum alloy. The sealing plate 1b, like the outer can 1a, is manufactured from a metal plate such as aluminum or an aluminum alloy. The sealing plate 1b is inserted into the opening of the outer can 1a, and the boundary between the outer periphery of the sealing plate 1b and the inner periphery of the outer can 1a is irradiated with a laser beam to the boundary, thereby laser welding the sealing plate 1b to the outer can 1a and hermetically fixing it thereto.
(Electrode terminal 2)

As shown in Figure 4 etc., the battery cell 1 has a terminal surface 1X formed by the sealing plate 1b, which is the top surface, and positive and negative electrode terminals 2 are fixed to both ends of this terminal surface 1X. The electrode terminals 2 have cylindrical protrusions. However, the protrusions do not necessarily have to be cylindrical, and can also be polygonal or elliptical.

The positions of the positive and negative electrode terminals 2 fixed to the sealing plate 1b of the battery cell 1 are such that the positive and negative electrodes are symmetrical. As a result, as shown in FIG. 4 and other figures, the battery cells 1 are stacked in a reversed state, and adjacent positive and negative electrode terminals 2 that are close to each other are connected by a bus bar, so that adjacent battery cells 1 can be connected in series. Note that the present invention does not specify the number of battery cells that make up the battery stack and their connection state. The number of battery cells that make up the battery stack and their connection state can be changed in various ways, including other embodiments described below.

The multiple battery cells 1 are stacked so that the thickness direction of each battery cell 1 is the stacking direction to form a battery stack 10. In the battery stack 10, the multiple battery cells 1 are stacked so that the terminal surfaces 1X on which the positive and negative electrode terminals 2 are provided, and in FIG. 4, the sealing plate 1b, are flush with each other.

The battery stack 10 may have an insulating spacer 16 between adjacent stacked battery cells 1. The insulating spacer 16 is made of an insulating material such as resin in the form of a thin plate or sheet. The insulating spacer 16 is a plate having a size approximately equal to the size of the opposing surface of the battery cell 1. The insulating spacer 16 can be stacked between adjacent battery cells 1 to insulate the adjacent battery cells 1 from each other. Note that, as the spacer to be placed between adjacent battery cells, a spacer having a shape in which a flow path for cooling gas is formed between the battery cell and the spacer can also be used. The surface of the battery cell can also be covered with an insulating material. For example, the surface of the exterior can excluding the electrode portion of the battery cell can be covered with a shrink film such as PET resin. In this case, the insulating spacer may be omitted. In addition, in a power supply device in which multiple battery cells are connected in parallel or in series, insulating spacers are interposed between the battery cells connected in series to insulate them from each other, while no voltage difference occurs between adjacent exterior cans between battery cells connected in parallel to each other, so the insulating spacer between these battery cells can also be omitted.

Furthermore, the power supply device 100 shown in Figure 4 has end plates 20 arranged on both end faces of the battery stack 10. End surface spacers 17 may be interposed between the end plates 20 and the battery stack 10 to insulate them. The end surface spacers 17 can also be made into a thin plate or sheet shape using an insulating material such as resin.

In the power supply device 100 according to the first embodiment, the electrode terminals 2 of adjacent battery cells 1 are connected to each other by a bus bar in a battery stack 10 in which multiple battery cells 1 are stacked on top of each other, thereby connecting the multiple battery cells 1 in parallel and in series. A bus bar holder may also be disposed between the battery stack 10 and the bus bar. By using the bus bar holder, the multiple bus bars can be disposed in fixed positions on the upper surface of the battery stack while insulating the multiple bus bars from each other and insulating the terminal surfaces of the battery cells from the bus bar.

Busbars are manufactured by cutting and processing metal sheets into a desired shape. The metal sheets that make up the busbars can be made of metals that have low electrical resistance and are lightweight, such as aluminum sheets or copper sheets, or alloys of these. However, other metals that have low electrical resistance and are lightweight, or alloys of these metals, can also be used for the metal sheets of the busbars.
(End plate 20)

4, the end plates 20 are arranged at both ends of the battery stack 10 and are fastened via a pair of left and right fastening members 15 arranged along both side surfaces of the battery stack 10. The end plates 20 are located at both ends of the battery stack 10 in the stacking direction of the battery cells 1, outside the end spacers 17, and sandwich the battery stack 10 from both ends.
(Fastening member 15)

Both ends of the fastening member 15 are fixed to end plates 20 arranged on both end faces of the battery stack 10. The end plates 20 are fixed with a plurality of fastening members 15, thereby fastening the battery stack 10 in the stacking direction. As shown in Figures 2 to 4, each fastening member 15 is made of metal with a predetermined width and thickness that fits along the side of the battery stack 10, and is arranged opposite both side faces of the battery stack 10. This fastening member 15 can be made of a metal plate such as iron, preferably a steel plate. The fastening member 15 made of a metal plate is bent by press molding or the like to be formed into a predetermined shape.

As shown in the exploded perspective view of Figure 4, the fastening member 15 has end plate locking pieces 15b bent into an L shape at the longitudinal ends of the fastening main surface 15a, i.e., at both ends in the stacking direction of the battery stack 10. The end plate locking pieces 15b are screwed into the end plates 20 to secure the end plates 20 together.

As shown in the exploded perspective view of Figure 4 and the vertical cross-sectional view of Figure 5, the fastening member 15 has a lower end of the fastening surface 15a bent into an L-shape to form a lower plate connecting piece 15d. Furthermore, the upper end of the fastening surface 15a is bent to form a pressing piece 15c that presses against the edge of the upper surface of the battery stack 10. In this way, the fastening member 15 covers the upper and lower surfaces of the battery stack 10 from the corners on the left and right side surfaces of the battery stack 10.

The pressing pieces 15c are separated for each battery cell so that they can individually press the upper surfaces of the battery cells 1 of the battery stack 10. This allows each pressing piece 15c to press the battery cell 1 against the lower plate 50 independently of the adjacent pressing pieces 15c. In this way, each battery cell 1 is prevented from floating up from the lower plate 50 and is held in the height direction, and each battery cell 1 can be kept from shifting in position in the vertical direction even if vibrations, shocks, etc. are applied to the battery stack 10.

The shape of the fastening member 15 and the fastening structure with the end plate 20 can be appropriately made of known structures. For example, both ends of the fastening member may be flat without being bent into an L-shape, and configured to screw into the side of the end plate. Alternatively, the portion of the fastening member facing the side of the end plate may be configured as an engagement structure that engages in a stepped shape, and the fastening member may be further screwed into the side of the end plate in a state where it is engaged with the engagement structure.

The power supply device 100, which is made up of a large number of stacked battery cells 1, is configured to restrain the multiple battery cells 1 by connecting end plates 20 arranged at both ends of the battery stack 10 made up of the multiple battery cells 1 with fastening members 15. By restraining the multiple battery cells 1 via the highly rigid end plates 20 and fastening members 15, it is possible to suppress the expansion, deformation, relative movement, and malfunction due to vibration of the battery cells 1 caused by charging/discharging and deterioration.

An insulating sheet is also interposed between the fastening members 15 and the battery stack 10. The insulating sheet is made of an insulating material, such as resin, and provides insulation between the metal fastening members 15 and the battery cells 1.

Note that the insulating sheet may not be necessary if the battery stack or its surfaces are insulated, for example if the battery cells are housed in an insulating case or covered with a resin heat-shrinkable tube, or if the surfaces of the fastening members are coated with an insulating paint or coating, or if the fastening members are made of an insulating material, etc. The insulating sheet may also be configured to serve as the bus bar holder that holds the bus bars described above.
(Heat transfer sheet 40)

The heat transfer sheet 40 is made of a material that is insulating and has excellent thermal conductivity. The heat transfer sheet 40 is elastic or flexible, and is deformed when pressed between the lower plate 50 and the battery stack 10, and is in close contact with the interface between them without any gaps, creating a thermally bonded state. Silicone resin or the like is preferably used as the heat transfer sheet 40. A filler such as aluminum oxide may be added to increase thermal conductivity.
(Low frictional resistance area 42)

It is also preferable to provide a low friction resistance area 42 on the upper surface of the heat transfer sheet 40 to reduce frictional resistance with the battery stack 10. For example, as shown in the cross-sectional view of FIG. 6, a sliding sheet of a separate member may be placed on the upper surface of the heat transfer sheet 40 as such a low friction resistance area 42. The sliding sheet is made of a material with lower friction resistance than the heat transfer sheet 40. This allows the upper surface of the heat transfer sheet 40 to slide when the battery stack 10 is displaced by expansion and contraction on the upper surface of the heat transfer sheet 40, thereby preventing wrinkles from occurring and maintaining a thermally bonded state. As such a sliding sheet, for example, a polyethylene terephthalate (PET) film is preferable, and in particular, a biaxially oriented polyethylene terephthalate film is suitable.

In addition, a region that limits frictional resistance may be provided on the surface of the heat transfer sheet. For example, the surface of the heat transfer sheet may be subjected to a surface treatment or processing such as a fluororesin coating to reduce frictional resistance. Alternatively, grease or oil may be applied to the surface of the heat transfer sheet.
(Lower Plate 50)

The lower plate 50 covers the underside of the battery stack 10. A metal heat sink with excellent thermal conductivity can be used for this lower plate 50. The lower plate 50 may also be equipped with a cooling mechanism, such as an internal refrigerant circulation path. This allows the battery stack 10 to be efficiently cooled and dissipated heat by refrigerant cooling, while the heat transfer sheet 40 can maintain an optimal thermal coupling state between the battery stack 10 and the lower plate 50.
(Fixing device)

The lower plate 50 is provided with a plate fixing mechanism 6 for fixing to the power supply target device PD. As described above, in the example of Figs. 1 to 3, the plate fixing mechanism 6 is a fixing tool for fixing the bracket 60. In the example of Figs. 2 to 3, the fixing tool is composed of a plate fixing screw hole 51 formed in the lower plate 50, a bracket fixing hole 63 opened in the bracket 60, and a plate fixing bolt 62 inserted into the plate fixing screw hole 51 and the bracket fixing hole 63. The plate fixing bolt 62 has a screw head 62a and a screw groove portion 62b. As shown in the enlarged cross-sectional view of Fig. 7, the plate fixing bolt 62 inserted into the plate fixing screw hole 51 of the lower plate 50 and the bracket fixing hole 63 of the bracket 60 is configured so that its upper surface is lower than the main surface of the lower plate 50. Specifically, as shown in the enlarged view of the main part of Fig. 7, the upper surface of the screw head 62a of the plate fixing bolt 62 is designed to be lower by a height d1 than the main surface of the lower plate 50. As a result, when the lower plate 50 is fixed to the bracket 60 by the plate fixing mechanism, the plate fixing bolts 62 do not protrude from the plate fixing screw holes 51 to the upper surface. This prevents the plate fixing bolts 62 from hindering the sliding of the battery cells 1, while allowing for displacement of the battery stack 10 due to expansion or contraction of the battery cells 1 on the upper surface of the lower plate 50 with the connecting structure described below.
(Connection structure 5)

Furthermore, as shown in the enlarged cross-sectional view of Figure 7 and the side view of Figure 8, the power supply device 100 is provided with a connection structure 5 that connects the lower plate 50 and the fastening member 15 in a state that allows displacement. This allows the power supply device 100 to be stably fixed to the device PD to which power is supplied without transmitting displacement due to expansion and contraction of the battery cells 1 to the lower plate 50.

In particular, in a long power supply device 700 as shown in FIG. 14, which has a large number of stacked battery cells, the amount of displacement of the entire length of the battery stack due to expansion and contraction of the battery cells is large, so a large load is placed on the bracket 760 that fixes the power supply device 700 to the power supply target device PD. For example, when the number of battery cells increases from 12 to 36, the amount of expansion increases by about 2.7 times, and the stress load also increases proportionally. For such long power supply devices, a power supply device having the plate fixing mechanism 6 and the connecting structure 5 described above is advantageous. Specifically, this is effective for long power supply devices in which the rectangular aspect ratio of the battery stack 10 in a plan view is 5 or more. For example, for a power supply device in which the long side of the battery stack 10 is approximately 1 m to 1 m20 cm and the short side is approximately 140 mm to 170 mm, a situation in which a large load is placed on the fixing structure that fixes the battery stack 10 to the power supply target device can be avoided.

The connection structure 5 is composed of, for example, an elongated hole formed in either the fastening member 15 or the lower plate 50, a hole formed in the other, and an elongated screw inserted through the elongated hole and hole. In the example shown in the cross-sectional view of Figure 7, the elongated hole is formed in the fastening member 15, and the hole is formed in the lower plate 50. The elongated hole extends along the stacking direction of the multiple battery cells. The hole is formed in a position corresponding to the elongated hole. By inserting and screwing the elongated hole and hole into the elongated hole, it is possible to allow relative displacement of the interface between the lower plate 50 and the fastening member 15.

The connecting structure 5 preferably includes a round hole formed in either the fastening member 15 or the lower plate 50, a second hole portion formed in the other, and a round hole screw inserted through the round hole and the second hole portion. In the example shown in the exploded perspective views of Figures 3 to 4, a round hole (notch 15g described later) is formed in the fastening member 15, and a second hole portion 52 is formed in the lower plate 50. The round hole is formed in the center of the stacking direction of the multiple battery cells 1. In the example of Figure 3, etc., a round hole is formed in the center of the longitudinal direction of the fastening member 15, and oblong holes are formed on both ends. In this way, by fixing the center in the longitudinal direction as a round hole as the connecting structure 5, while making the ends on both sides where the expansion and contraction of the battery stack 10 accumulates and becomes large, as shown in Figure 8, it is possible to connect the fastening member 15 and the lower plate 50 in a state where the battery stack 10 can slide on the lower plate 50.

Furthermore, it is preferable that the plate fixing mechanism 6 and the connecting structure 5 are formed coaxially. In other words, by sharing the screws and screw holes that constitute the plate fixing mechanism 6 and the connecting structure 5, it is possible to connect the lower plate 50 to the battery stack 10 and fix the lower plate 50 to the bracket 60 at one place, simplifying the configuration and reducing the number of parts. In the example of FIG. 7, the plate fixing screw hole 51 formed in the lower plate 50 that constitutes the plate fixing mechanism 6 functions as the hole that constitutes the connecting structure 5. In addition, the plate fixing bolt 62 inserted into the plate fixing screw hole 51 and the bracket fixing hole 63 that constitute the plate fixing mechanism 6 functions as the long hole screw that constitutes the connecting structure 5.

The connecting structure 5 shown in Figures 3 and 4 is composed of a notch 15g which is a round hole, and a fastening member screw hole 15f which is an elongated hole, which are formed in the lower plate connecting piece 15d of the fastening member 15, and a plate fixing screw hole 51 and a second hole portion 52 which are formed in the lower plate 50, and a plate fixing bolt 62 and a round hole screw 53 which are inserted therethrough. Note that in this example, the notch 15g is formed as a round hole in the middle of the lower plate connecting piece 15d, but it goes without saying that a through hole may be used instead of the notch.

7, the connecting structure 5 has a plate fixing bolt 62 screwed into a fastening member screw hole 15f formed in the lower plate connecting piece 15d of the fastening member 15 and a plate fixing screw hole 51 formed in the lower plate 50. The fastening member screw hole 15f is an elongated hole along the expansion and contraction direction of the battery stack 10, so that the lower plate 50 and the fastening member 15 are screwed together while allowing sliding at the interface. In this example, gaps d2 and d3 are formed between the inner surface of the fastening member screw hole 15f and the periphery of the threaded groove portion 62b of the plate fixing bolt 62. Even if the battery stack 10 expands by the amount of the gaps d2 and d3, the expansion is not transmitted to the lower plate 50, and the load on the fixing structure between the lower plate 50 and the power supply target device PD via the bracket 60 can be reduced.

The power supply device 100 described above can be used as a vehicle power source that supplies power to a motor that runs an electric vehicle. Electric vehicles that can be equipped with the power supply device 100 include hybrid cars and plug-in hybrid cars that run on both an engine and a motor, and electric cars that run only on a motor, and the power supply device 100 is used as a power source for these vehicles. Note that an example will be described in which a large-capacity, high-output power supply device is constructed by connecting a large number of the above-mentioned power supply devices 100 in series or parallel to obtain power to drive an electric vehicle, and further adding a necessary control circuit.
(Power supply unit for hybrid vehicles)

FIG. 9 shows an example of a power supply device 100 mounted on a hybrid vehicle that runs on both an engine and a motor. The vehicle HV mounted with the power supply device 100 shown in this figure includes a vehicle body 91, an engine 96 and a motor 93 for running the vehicle body 91, wheels 97 driven by the engine 96 and the motor 93 for running, a power supply device 100 for supplying power to the motor 93, and a generator 94 for charging the battery of the power supply device 100. The power supply device 100 is connected to the motor 93 and the generator 94 via a DC/AC inverter 95. The vehicle HV runs on both the motor 93 and the engine 96 while charging and discharging the battery of the power supply device 100. The motor 93 is driven in an area where the engine efficiency is poor, such as during acceleration or low-speed running, to run the vehicle. The motor 93 is driven by power supplied from the power supply device 100. The generator 94 is driven by the engine 96 or by regenerative braking when braking the vehicle, and charges the battery of the power supply device 100. As shown in Fig. 9, the vehicle HV may be provided with a charging plug 98 for charging the power supply device 100. The power supply device 100 can be charged by connecting this charging plug 98 to an external power source.
(Power supply unit for electric vehicles)

FIG. 10 shows an example of mounting the power supply device 100 on an electric vehicle that runs only on a motor. The vehicle EV mounted with the power supply device 100 shown in this figure includes a vehicle body 91, a motor 93 for driving the vehicle body 91, wheels 97 driven by the motor 93, a power supply device 100 that supplies power to the motor 93, and a generator 94 that charges the battery of the power supply device 100. The power supply device 100 is connected to the motor 93 and the generator 94 via a DC/AC inverter 95. The motor 93 is driven by power supplied from the power supply device 100. The generator 94 is driven by energy generated when the vehicle EV is subjected to regenerative braking, and charges the battery of the power supply device 100. The vehicle EV also includes a charging plug 98, which can be connected to an external power source to charge the power supply device 100.
(Power supply device for power storage device)

Furthermore, the present invention does not limit the use of the power supply device to a power source for a motor that runs a vehicle. The power supply device according to the embodiment can also be used as a power source for a power storage device that charges a battery with electricity generated by solar power generation, wind power generation, etc. and stores the electricity. Figure 11 shows a power storage device that charges the battery of the power supply device 100 with a solar cell 82 and stores the electricity.

The power storage device shown in FIG. 11 charges the battery of the power supply device 100 with power generated by a solar cell 82 arranged on the roof or rooftop of a building 81 such as a house or factory. This power storage device charges the battery of the power supply device 100 with a charging circuit 83 using the solar cell 82 as a charging power source, and then supplies power to a load 86 via a DC/AC inverter 85. For this reason, this power storage device has a charging mode and a discharging mode. The power storage device shown in the figure connects the DC/AC inverter 85 and the charging circuit 83 to the power supply device 100 via a discharge switch 87 and a charge switch 84, respectively. The discharge switch 87 and the charge switch 84 are switched ON/OFF by the power storage device's power supply controller 88. In the charge mode, the power supply controller 88 switches the charge switch 84 to ON and the discharge switch 87 to OFF to allow charging from the charging circuit 83 to the power supply device 100. Furthermore, when charging is completed and the battery is fully charged, or when a capacity equal to or greater than a predetermined value is charged, the power supply controller 88 switches the charging switch 84 to OFF and the discharging switch 87 to ON to switch to a discharging mode, permitting discharging from the power supply device 100 to the load 86. Furthermore, if necessary, the charging switch 84 can be turned ON and the discharging switch 87 can be turned ON to supply power to the load 86 and charge the power supply device 100 at the same time.

Furthermore, although not shown, the power supply device can also be used as a power source for a power storage device that uses late-night power at night to charge and store electricity in a battery. A power supply device that is charged with late-night power is charged with late-night power, which is surplus electricity from power plants, and can output electricity during the day when the power load is high, thereby limiting daytime peak power to a low level. Furthermore, the power supply device can also be used as a power source that charges with both the output of solar cells and late-night power. This power supply device makes effective use of both the power generated by solar cells and late-night power, and can store electricity efficiently while taking into account the weather and power consumption.

The above-mentioned energy storage system can be ideally used for a variety of applications, including as a backup power supply that can be mounted on a computer server rack, as a backup power supply for wireless base stations for mobile phones and the like, as a power storage device for home or factory use, as a power source for street lights, as an energy storage device combined with a solar cell, and as a backup power supply for traffic lights and road traffic indicators.

The power supply device and vehicle equipped with the same according to the present invention can be suitably used as a high current power supply for the power supply of motors that drive electric vehicles such as hybrid cars, fuel cell vehicles, electric cars, and electric motorcycles. Examples include power supply devices for plug-in hybrid electric cars, hybrid electric cars, electric cars, etc. that can switch between EV driving mode and HEV driving mode. They can also be used as backup power supplies that can be mounted on computer server racks, backup power supplies for wireless base stations for mobile phones, etc., power supplies for home and factory storage, power supplies for street lights, power storage devices combined with solar cells, backup power supplies for traffic lights, etc.

100, 700, 900...power supply device, 1...battery cell, 1X...terminal surface, 1a...outer can, 1b...sealing plate, 2...electrode terminal, 5...connection structure, 6...plate fixing mechanism, 10...battery stack, 14...battery side plate, 15...fastening member; 15a...main fastening surface; 15b...end plate locking piece; 15c...pressure piece; 15d...lower plate connecting piece; 15f...fastening member screw hole; 15g...notch, 16...insulating spacer, 17...end surface spacer, 20...end plate, 40...heat transfer sheet, 42...low friction resistance area, 50...lower plate, 51...plate fixing screw hole, 52...second hole portion, 53...round hole screw, 60, 760, 960... Bracket, 62...plate fixing bolt; 62a...screw head; 62b...thread groove portion; 63...bracket fixing hole; 81...building; 82...solar cell; 83...charging circuit; 84...charging switch; 85...DC/AC inverter; 86...load; 87...discharging switch; 88...power supply controller; 91...vehicle body; 93...motor; 94...generator; 95...DC/AC inverter; 96...engine; 97...wheel; 98...charging plug; 901...battery cell; 902...spacer; 903...end plate; 704, 904...bind bar; PD...device to be supplied with power; DI...recess; d1...height; d2, d3...gap; HV, EV...vehicle

Claims (10)

A power supply device for fixing to a power supply target device,
A plurality of battery cells having rectangular exterior cans;
a pair of end plates that cover both side end surfaces of a battery stack formed by stacking the multiple battery cells;
a lower plate covering the lower surface of the battery stack;
a plurality of fastening members each having a plate shape extending along a stacking direction of the plurality of battery cells, the fastening members being disposed on opposing side surfaces of the battery stack and fastening the end plates together in a state in which the battery stack is placed on an upper surface of the lower plate;
a plate fixing mechanism for fixing the lower plate to a device to be supplied with power;
a connection structure that connects the lower plate and the fastening member in a state that allows displacement;
Equipped with
The connecting structure is
a slot formed in either the fastening member or the lower plate and extending along a stacking direction of the plurality of battery cells;
a hole formed in the other of the fastening member or the lower plate at a position corresponding to the long hole;
a slotted screw that is inserted through the slotted hole and the hole and screwed into the slotted hole in a state that allows relative displacement of the interface between the lower plate and the fastening member;
having
The connecting structure further comprises:
a circular hole formed in a center portion in a stacking direction of the plurality of battery cells of either the fastening member or the lower plate;
a round hole screw that is screwed into the other of the fastening member or the lower plate at a position corresponding to the round hole;
Equipped with
the long holes are formed in either the fastening member or the lower plate at both ends in a stacking direction of the plurality of battery cells,
The elongated screw is screwed into the other of the fastening member or the lower plate at a position corresponding to the elongated hole . 2. The power supply device according to claim 1,
the plate fixing mechanism includes a bracket for fixing the lower plate to a power supply target device;
A power supply device that is a fixture for fixing the lower plate and the bracket. 3. The power supply device according to claim 2,
The bracket is fixed in a position so as to protrude from each of the pair of end plates. 4. The power supply device according to claim 2 or 3,
The plate fixing mechanism includes:
a plate fixing screw hole formed in the lower plate;
a bracket fixing hole opened in the bracket;
a plate fixing bolt inserted into the plate fixing screw hole and the bracket fixing hole;
It is composed of
A power supply device configured such that the plate fixing bolts inserted into the plate fixing screw holes and the bracket fixing holes have their upper surfaces at a height lower than the main surface of the lower plate. The power supply device according to any one of claims 1 to 4 ,
The plate fixing mechanism and the connecting structure are formed coaxially,
a plate fixing screw hole formed in the lower plate constituting the plate fixing mechanism is a hole portion formed in the lower plate constituting the connecting structure,
The plate fixing bolt that constitutes the plate fixing mechanism and is inserted into the plate fixing screw hole and the bracket fixing hole is a long hole screw that constitutes the connecting structure and is screwed into the hole portion in a state that allows relative displacement of the interface between the lower plate and the fastening member. The power supply device according to any one of claims 1 to 5 , further comprising:
a heat transfer sheet interposed between an upper surface of the lower plate and a lower surface of the battery stack, thermally coupling the lower plate and the battery stack. 7. The power supply device according to claim 6 ,
The power supply device, wherein the heat transfer sheet is made of an elastic insulating material. The power supply device according to any one of claims 1 to 7 ,
a rectangular battery stack having an aspect ratio of 5 or greater in a plan view; A vehicle equipped with the power supply device according to any one of claims 1 to 8 ,
A vehicle comprising the power supply device, a motor for driving supplied with power from the power supply device, a vehicle body mounting the power supply device and the motor, and wheels driven by the motor to drive the vehicle body. A power storage device comprising the power supply device according to any one of claims 1 to 8 ,
A power storage device comprising the power supply device and a power supply controller that controls charging and discharging to the power supply device, the power supply controller enabling charging of the battery cells using external power and controlling the charging of the battery cells.

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